1) Yes, DVD-RAM is the safest optical media solution against data corruption.
2) This was not a question, was it?
3) Assuming that you want to backup your data, not to exchange it with non-Windows systems, choose ISO compilation.
4) Indeed, finalizing the medium will disallow you to come back and add files again, except if you erase your entire medium to start from scratch.
Software Development, InCD Project Manager
Nero AG - Im Stoeckmaedle 18
76307 Karlsbad - Germany
fax: +49 (0)7248 928 299 http://www.nero.com